A typical example of a display device is a television (TV). With the recent development of broadcast technology, a broadcast signal transmission method has advanced and an interest in a digital TV based on a digital transmission method has increased.
The digital TV transmits an analog broadcast signal in a digital format, thus making it possible to minimize a noise effect and to provide an easy reproduction of an original image.
Unlike a conventional display device capable of receiving only airwave channel, a recent display device can receive various broadcast channels through a cable or satellite broadcast, thus providing about 50 to about 100 or more channels to users.
Also, a user performs an automatic channel search if a display device is initially installed or if a channel search is necessary due to a signal environment change.
Herein, the automatic channel search is a technology that determines the channel effectiveness sequentially from the start channel number to the last channel number and constructs a channel map on the basis of the effective channel information.
Because the automatic channel search is performed on all the channels, it requires a lot of time and thus provides a band or channel skip function for the user's convenience.